138880661 has 2 divisors, whose sum is σ = 138880662. Its totient is φ = 138880660.

The previous prime is 138880627. The next prime is 138880717. The reversal of 138880661 is 166088831.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 75359761 + 63520900 = 8681^2 + 7970^2 .

It is an emirp because it is prime and its reverse (166088831) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 138880661 - 2¹⁴ = 138864277 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (138880561) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 69440330 + 69440331.

It is an arithmetic number, because the mean of its divisors is an integer number (69440331).

Almost surely, 2^138880661 is an apocalyptic number.

It is an amenable number.

138880661 is a deficient number, since it is larger than the sum of its proper divisors (1).

138880661 is an equidigital number, since it uses as much as digits as its factorization.

138880661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 55296, while the sum is 41.

The square root of 138880661 is about 11784.7639348440. The cubic root of 138880661 is about 517.8618577382.

The spelling of 138880661 in words is "one hundred thirty-eight million, eight hundred eighty thousand, six hundred sixty-one".